The present invention relates to cutting elements for drill bits and, in particular, to cutting elements which facilitate installation in a drill bit.
One type of cutting element used in rotary drilling operations in earth formations comprises an abrasive composite or compact mounted on a stud. The composite typically comprises a diamond layer adhered to a cemented carbide substrate, e.g., tungsten carbide cemented by a metal binder such as cobalt. The substrate is brazed to the stud and the stud is mounted in a drill bit by being installed into predrilled holes in the drill bit and is secured therein by press-fit or by brazing. Such a cutting element is depicted, for example, in U.S. Pat. No. 4,325,439.
Installation of the cutting element is performed by means of a pusher tool which engages the top of the cutting element and pushes it into the predrilled bore in the drill bit. The pusher tool typically is of inverted U-shape, e.g., yoke-shaped, having a pair of legs which straddle the sides of the cutting element (e.g., see U.S. Pat. No. 4,325,439 disclosing a pusher 50). In performing the pushing operation, downward forces applied to the composite tend to shear the composite off the stud. Furthermore, in the case of a stud possessing an extension or boss upon which the composite is mounted as disclosed in copending Application Ser. No. 06/804,864, filed December 5, 1985, such downward forces may bend the boss in cantilever fashion and cause it to break off.